MARINE UNIVALVES 143 



both ends, does not live on our coast, but is found in 

 great abundance in the West Indies. 



MargineJla varia^ Sby., the Colored Marginella, 

 has a pretty little shell, about the size and shape of 

 a fat grain of wheat. It has a very short, rounded 

 spire, a long aperture, and a plaited columella. Its 

 surface is very smooth and glossy, and varies in color 

 from white to brown, the shades being often laid on 

 in bands and stripes. It is a southern species, and is 

 often found on rocks between tides. Several other 

 species of Marginella exist on our coast, but they are 

 very small. , ^. .;T:^]i#j 



Mitra ida, Melville, Ida's Miter-shell, 

 is shown in Figure 115. It is a dusky rela- 

 tive of the beautiful and brilliant Miter- 

 shells which are found in the vicinity of 

 Australia. Our species is by no means 

 gaudy, either in color or ornamentation, but 

 it has a plain, smooth shell, which is almost 

 black, and is wholly devoid of the gay Fig. il^. xg 

 trimmings of its relatives. The columella 

 is ridged with three strong, oblique folds, which are 

 very conspicuous. The cut represents a small speci- 

 men, but dead shells are not infrequently found that 

 are fully two inches in length, though they are almost 

 always somewhat broken. Fresh specimens have a 

 black epidermis, but worn shells are chestnut-brown 

 in color, with a whitish interior. A large, perfect 

 specimen was recently found at Monterey. 



There has been much discussion as to the true 

 name of this species. In most books it has been 

 called M. maura^ Swains. That name was appar- 



